The determination of resonance parameters and the influence of finite energy resolution

Abstract The influence of finite energy resolution on observed energy distributions is discussed. The distributions considered correspond to resonances as well as their interference with background. The enhancement of the width, reduction of the height and increase of the product of these resonance parameters are studied as functions of the ratio of proper width and r.m.s. energy spread. Unrestricted values of this ratio are admitted. Results in graphical form allow estimates to be made of the importance of the distortion effect for varying experimental situations. Using published results for the width of the meson S(1935) it is argued that its width is about half the accepted value. Considering large values of the mentioned ratio, a non-negligible influence is found to persist up to values of about 60. Corresponding corrections are given. The asymptotic forms of the rule for combining widths for small and large values of the ratio are derived and compared with the numerical results.